Respiratory System

• The process of exchanging gases between the atmosphere and body cells is called respiration.

Events of respiration

• Exchange of gases between air in the lungs and the blood is called external respiration

• Gas exchange between blood and body cells is called internal resp.

Pathway of air in the body• Nose• Nasal cavity• Pharynx• Larynx• Trachea• Bronchial tree• Alveoli

• The alveoli are the site for gas exchange in the body

Breathing Mechanism

• Remember: Diffusion is a passive process, no energy is required.

• Normal atmospheric pressure is 760 mm Hg

Inspiration• The diaphragm contracts (flattens) and

moves downward. • Thoracic cavity enlarges; alveoli increase in

diameter• The pressure within the lungs (and alveoli)

falls about 2mm Hg below normal (758 mm Hg)

• Air is sucked into the lungs bc of negative pressure

Expiration• Diaphragm relaxes (curved)• Thoracic cavity decreases in size and

alveoli diameter decreases• Lung (and alveoli) pressure increases to

about 1 mm Hg above normal (761 mm Hg)

• Air is forced out of lungs (passive process)

Smoking

• Smoking destroys the movement of cilia in the resp. system

• This allows dirt and debris to enter the resp. system and mucus builds up in the nasal cavity

• this build up results in smokers’ cough (an effort to manually breakup the accumulated mucus)

Smoking

• Smokers’ cough leads to chronic bronchitis (infection of the bronchiole tubes)

• Mucus production increases, the bronchioles thicken (less diameter)more difficult to breathe

• Bronchioles lose elasticity and cannot adjust to pressure changes

Smoking • Air pressure increases enough to burst

alveoli- this condition is called emphysema• With emphysema coughing worsens along

with fatigue and wheezing• Emphysema can progress to cancer• 80% of all lung cancer is caused from

smoking• 13% of those with lung cancer do not live

past 5 years

Total lung capacity

• the vital capacity plus the residual volume

• average = 5800ml • varies with age, sex, and body

size

Respiratory Volumes• One inspiration followed by

expiration is a respiratory cycle• Tidal Volume-the amount of air that

enters or leaves the lungs during a normal resting respiration (about 500 ml)

Respiratory Volumes

• During forced maximal inspiration (deep breathing) additional quantities of air enter the lungs; this is called inspiratory reserve volume.

• This can equal about 3,000 ml

Respiratory Volumes• During maximal forced ex(it)piration,

about 1100ml of additional air can be expelled from the lungs; this is the expiratory reserve volume.

• This leaves about 1200 ml of air in the lungs at all times – this is called residual volume

Vital capacity• The total of the inspiratory reserve

volume, the tidal volume, and the expiratory reserve volume is the vital capacity (max in, normal, max out)

• The adult average is about 4,600 ml.• This is the maximum amount of air a

person can exhale after they have taken the deepest breath possible

Inspiratory capacity

• The tidal volume plus the inspiratory reserve volume.

• This is the maximum amount of air a person can inhale

• average – 3500 ml

Functional residual capacity

• the expiratory reserve volume plus the residual volume

• equals the amount of air left in the lungs after normal expiration

• average = 2300ml

Total lung capacity• A spirometer is used to measure

lung capacity• Lung capacity measurements can

be used as an initial diagnostic tool for emphysema, pneumonia, lung cancer, and asthma

Gas Transport

• Oxygen is carried in the blood bound to the hemoglobin in RBC

• Each hemoglobin molecule can combine with only four oxygen molecules

• Hypoxia – oxygen deficiency

Alveoli

Hemoglobin

Respiratory Disorders

Pneumonia an infection of the lungs, which can be caused by

a variety of microorganisms, including viruses, bacteria, fungi, and parasites

causes inflammation of the lungs and mucus in alveoli

symptoms: fever, chills, cough, unusually rapid breathing, breathing with grunting or wheezing sounds, chest pain

treated with antibiotics, antiviral meds

Tiger Woods w pneumonia

Bronchitis viral infection of the bronchial tree bronchioles swell and mucus (thick fluid)

forms inside them, making it hard to breathe

symptoms: coughing up mucus and wheezing

treated with asthma medicines to reduce swelling and ease breathing

Bronchitis

Emphysema chronic lung disease usually caused by

smoking damage to the alveoli symptoms: Shortness of breath, barrel-

shaped chest, wheezing, fatigue, losing weight without trying

treatment: no cure, but symptoms can be eased with supplemental oxygen and other meds

Asthma chronic respiratory disease causing airway

inflammation; the airways in the lungs are overly sensitive to certain triggers

linked to allergies, heredity, environment, weight symptoms: attacks of wheezing, coughing, chest

constriction & labored breathing treated with meds such as inhaled steroids/anti-

inflammatory

Tuberculosis disease caused by bacteria that attack the lungs bacteria destroy lung tissue and can actually create

a hole in the lung symptoms: a bad cough, pain in the chest,

coughing up blood, fever, fatigue, chills treated with antibiotics latent TB (bacteria in body but not active causes

small bump on test) vs. active TB (bacteria actively attacking lung tissue)

No bump means on TB skin test means you are negative for TB

Tuberculosis

Cystic Fibrosis hereditary, recessive, caused by a gene/protein

defect chloride can’t be transported out of cells, so water

diffuses indries out mucus, causing it to clog affect organs

affects lungs (more infections)& pancreas (prevents digestive enzymes from reaching intestines, causing decreased nutrient absorption)

treatments: antibiotics for infections, exercises to remove mucus from lungs, digestive enzymes mixed into foods

Cystic Fibrosis

Lung Cancer Cigarette smoking causes an estimated 443,000 deaths each year, including approximately

49,400 deaths due to exposure to secondhand smoke.

Lung cancer is the leading cause of cancer death among both men and women in the United States, and 90 percent of lung cancer deaths among men and approximately 80 percent of lung cancer deaths among women are due to smoking.

In 2009, approximately 20.6 percent of U.S. adults were cigarette smokers.

Nearly 20 percent of high school students smoke cigarettes.(See Tobacco Statistics Snapshot for references for this information.)

Smoking causes many other types of cancer, including cancers of the throat, mouth, nasal cavity, esophagus, stomach, pancreas, kidney, bladder, and cervix, and acute myeloid leukemia.

People who smoke are up to six times more likely to suffer a heart attack than nonsmokers, and the risk increases with the number of cigarettes smoked. Smoking also causes most cases of chronic lung disease.

In 2009, approximately 20.6 percent of U.S. adults were cigarette smokers.

Nearly 20 percent of high school students smoke cigarettes.

Last 2 slides are copied from www.cancer.gov website